Calculating the Incalculable: Is SAI the Lesser of Two Evils?

In a forthcoming article in Ethics and International Affairs, Christopher J. Preston uses the doctrine of double effect to claim that hypothetical climate engineers might very well be less culpable for climate harms than those who continue to emit greenhouse gases. In an invited response for the journal, I claim that his argument is unpersuasive. His argument rests shakily on the ability to determine and quantify climate harms and to distinguish forensically between their causes. He is also largely silent about the distributional effects of these harms and their ethical and political ramifications.